In uplink of W-CDMA, since user equipments (UE) in the same cell use scramble codes specific to users and reception is non-orthogonal, fast transmission power control (TPC) is essential to reduce the effect of multi-user interference (i.e. the near-far problem).
Meanwhile, in the LTE (Long Term Evolution) system defined by 3 GPP Release 8 (hereinafter, referred to as “Rel-8 LTE”), in uplink is adopted SC-FDMA (Single-Carrier Frequency Division Multiple Access) radio access that actualizes low Peak-to Average Power Ratio (PAPR) and that is effective at increasing coverage. Accordingly, by scheduling by the base station apparatus, basically, since radio resources having some frequency and time are allocated to a UE, orthogonality in the frequency and time domains is achieved among users in the same cell. Therefore, from the viewpoint of suppressing multi-user interference in the same cell, fast TPC is not always essential. However, in Rel-8 LTE, since frequency is reused per one-cell, interference from adjacent cells is significant, and particularly, the interference level from the UE existing at the cell edge is high. Therefore, it is necessary to apply TPC also in LTE to compensate for such adjacent-cell interference and maintain certain reception quality.
In uplink of Rel-8 LTE are defined 1) Physical Random Access Channel (PRACH), 2) Physical Uplink Shared Channel (PUSCH), and 3) Physical Uplink Control Channel (PUCCH). Particularly, the PUSCH is a physical channel to transmit user data, and to the PUSCH is applied adaptive modulation and channel coding (AMC) corresponding to the reception channel state of the UE and frequency scheduling for assigning frequency blocks with high reception signal levels to each user optimally corresponding to reception channel states of a plurality of users. To respond to the instantaneous fading variation, fast frequency scheduling and fast AMC is executed for each TTI (Transmission Time Interval) with a length of 1 msec. In this case, it is possible to respond to the instantaneous fading variation by adaptive rate control by AMC, and slow TPC is used to respond to propagation loss from the base station apparatus and variations in adjacent-cell interference. The transmission power control of the PUSCH in uplink is controlled by a combination of open-loop TPC performed by parameters (Po, α, etc.) notified from the base station apparatus at relatively long intervals and a propagation loss value measured by the mobile station apparatus, and closed-loop TPC by TPC command notified at relatively short intervals to compensate for intermediate variations in the reception level due to shadowing and a setting error in transmission power in the UE (3GPP, TS36. 213). In closed-loop TPC performed between the base station apparatus and mobile station apparatus, for example, the base station apparatus calculates a difference between the reception SINR (Signal to Interference plus Noise Ratio) averaged by averaging time t and target reception SINR, notifies the mobile station apparatus of the difference as a TPC command, and thus controls the transmission power of the mobile station apparatus.